The shock absorber of the invention is directed toward use with motor vehicles of various types. More specifically, the shock absorber of this invention is especially adapted for use with motor vehicles such as the motorcycle, motor bite, dune buggy or similar vehicle having a dichotomy of end uses, both normal or usual and wholly recreational. In vehicles of the aforementioned type, there is a need to be able to drive said vehicles on improved and paved roads with ease and comfort and still be able to take the same vehicle over rough terrain over which recreational activities are engaged, while still having the attributes of a shock absorber system.
For example, in recent years the general public has become very interested in recreational sport-type racing or rally-type driving over courses offering both unusual excitement and a test of one's driving skill. Courses for such sport driving are makeshift in that hill or desert topography is chosen by the rider. In such instances, where the driver leaves an improved road and goes onto abnormal driving surfaces, there exists a need to be able to quickly adjust the shock absorbing characteristics of the shock absorbers employed upon his vehicle. Additionally, the dampening action of the shock absorbers must be of a type that will provide the best performance under the circumstances with which the vehicle is used to improve traction, cornering and overall rideability.
Moreover, there is a need for a shock absorber for all types of motor vehicles that is fabricated; of simple and rugged design and which lends itself to rebuilding should one or more of the components wear out from use. Additionally a high performance shock absorber should be sophisticated in design to permit heat dissipation of heat build up in the shock absorber itself and means taken to prevent aeration of a hydraulic fluid used in the shock absorber the end result of which will be to exercise some measure of control over the dampening action and to increase the longevity of the dampening fluid, such as hydraulic fluid, by viscosity control and the prevention of the breakdown of the lubricity thereof.
The prior art shock absorbers are deficient in the aspect that they do not employ a metering valve for the dampening fluid which is directly responsive to the differential pressures existing within the pressure tube of the shock absorber. That is, during recovery or rebound conditions of the shock absorber, there will be a tendency, in the normal case, of a dampening fluid such as hydraulic oil to return to the main reservoir as rapidly as possible. In the shock absorber of this invention the return of the hydraulic oil is metered and dependent upon the relative pressures existing within the shock absorber itself. Furthermore, shock absorbers of the prior art lack in performance adustment of their absorption qualities. While some may provide for some means of hydraulic fluid metering, such adjustment normally requires the dismantling or removal of the shock absorber from the vehicle with which it is associated, while our shock absorber is externally adjustable.
Additionally, the prior art shock absorbers do not provide for adjustability of the main shock absorber spring relative to the ends thereof and do not employ top-out and bottom-out springs for cooperation with the piston of the shock absorber. These as well as other features of the hereindisclosed shock absorber overcome the deficiencies existing in the prior art.